HAIIDWICKE'S SCIENC E.GOSbiP. 



85 



scenery, as be drives or walks from Gort, a small 

 town and station uu the Atlienay and Enuis Hall- 

 way. Previous, however, to leaving Govt, some time 

 might profitably be spent in exploring the natural 

 curiosities in its ncighbouihood ; their description, 

 however, may form the subject of the first chapter- 



PECULIAR TROUT OE LOCH ISLAY. 

 Br Jas. Thomson, E.G.S. 



ON the S.E. side of the inland of Tslay, in the 

 neighbourhood of Mc Arthur's Head, and 

 extending inland for several miles to the west, there 

 extend a series of bold conical quartzito hills. 

 The highest of these is 1,000 feet above the level of 

 the sea. Situated in the interstices of these hills 

 are numerous tarns, or small lochs. In one of 

 those lochs occur trout with abnormally-formed 

 caudal tins. The loch is known in the island by the 

 nameof Loch-Na-M:iorichcn (Gaelic), which means, 

 in English, the "Shelly Loch;" it lies on the western 

 extremity of a plateau about a mile in breadth, and 

 900 feet above sea-level. It is bouudcJ on the 

 east by Ben Vigar, 1,000 feet above sea-level ; on 

 the south by Ben Urrara, 1,400 feet above sea-level ; 

 and by Ben Van, about 1,200 feet above sea-level ; 

 while to the west there is a gradual descent to the 

 sea, which is about seven miles distant. The sur- 

 rounding of the plateau is in outline like an 

 amphitheatre on a grand scale. 



Ten hundred and forty-four yards to the east of 

 Loch-Na-Maorichen, at the base of the hills, there 

 is another loch, called Loch-Na-Breac (signifying, 

 in English, "Trout Loch)," which is about 100 

 feet above the level of Loch-Na-Maoricheu. 

 This is a deep, broad sheet of water, and is sur- 

 rounded by a ridge of quartzite rock, varying from 

 30 to CO feet in height, and forming a complete 

 barrier between it and Loch-Na-Maoricheu. This 

 loch abounds with small trout having the usually 

 formed hoiiiocercal caudal fins. The surplus v/ater 

 is carried away by a small runnel on the north side 

 of the loch, and flows down the valley on the north 

 side of Loeh-Na-ilaorichen, about 150 feet below 

 the level of the latter, joining the Lerggen stream 

 two miles further down the valley. 



To the south, and at a considerably lower level, 

 are several small lochs, in which no fish have been 

 found during the last thirty years. One of these. 

 Loch Urrara, is a dark, deep sheet of water, and 

 has been many times lislied, but in no instance have 

 any fish been caught. Loch-Na-Maorichen is 250 

 feet long by 234 feet broad, and is surrounded by a 

 ridge of quartzite rock, which on the west is CO feet, 

 on the north and east 30 feet, and on the south 

 10 feet above its level. On the N.E. there is a 

 small runnel 15 inches broad, and from 18 to a 



few inches deep. This outlet is partially filled with 

 water for a distance of 48 feet, where it is finally 

 lost to view. In descending the valley, there 

 is evidence of an old watercourse, which can be 

 traced down to the burn that carries away the 

 surplus water from Loch-Na-Breac. This old water- 

 course is well filled up with peat moss and surface 

 vegetation, while the surplus water, in rainy seasons, 

 can only be seen oozing tlu:ough the moss. It will 

 be apparent that there is now no connection between 

 Loch-Na-Maorichen and any other sheet or water- 

 course. 



FiiT. Co. 

 Peculiar Trout of Loch Islay. Var. a, Acuminate tail. 



On the south side of the loch there is evidence 

 of a second outlet, in the form of an elongated 

 depression, the bottom of which is covered by 

 angular fragments and masses of quartzite, similar 

 to what we now find around the south-eastern 

 margin of the loch ; but at present this outlet is 

 fully six feet above the level of the water in the 

 loch. In and surrounding the south-east margin of 

 the loch, an area is covered Vt'ith angular fragments 

 and boulders of quartzite rock. The surface of 

 these stones is dotted with numerous little black 

 oblong spots, which, when examined, are found to 

 contain the larvai of the little dark flies so frequently 

 found moving about under the banks and sheltered 

 places of pools and streams. 



Fig. 61. Peculiar Trout of Loch Islay. Var. b, Ruuudei tall. 



It has been asserted that the fish found.in this 

 loch feed upon small shells. Possibly this may 

 have arisen from its name, which, as before stated, 

 means " Shelly Loch." If there have been shells 

 in it, it must have been a long time ago, possibly 

 during the earlier part of the post-tertiary age, as 

 there is not the slightest trace of shells in the loch 

 now. This is testified by the contents of the 

 stomachs of the fish, four of which I have carefully 

 examined, and found to contain the larvse of insects, 

 flies, and several small fresh-water beetles. In 

 some of the stomachs were flies, larvse,.&c., all more 



